118 research outputs found
Qualidade da água e sua relação espacial com as fontes de contaminação antrópicas e naturais: bacia hidrográfica do rio São Domingos - RJ
The onset of the anomalous J/ suppression in Pb-Pb collisions at the CERN SPS
The suppression observed by the NA50 experiment is one of the most striking signatures for quark gluon plasma formation in Pb-Pb collisions at 158 AGeV. The production has been studied as a function of the centrality of the collision estimated via the forward energy EZDC released in a zero degree calorimeter (ZDC). The study of the correlation between the number of participant nucleons in the collisions, Npart, and EZDC allows to check whether the suppression pattern vs. EZDC is compatible with a sudden suppression mechanism expressed as a function of Npart
Charmonium production in Pb-Pb collisions
NA50The elaboration of specific media-planning is necessary to communicate with an opinion leader. Opinion leaders in 27 product categories are selected from a 10,000 sample of French representative consumers. Magazine is the favorite media of opinion leaders; the more important is the number of product categories in which a consumer is leaders, the greater the media consumption. Leaders do not systematically prefer the Internet, their preference appears to be category specific. However, a second study conducted among 600 brand website visitors shows that brand sites represent a major information source for the leaders
Observation of a threshold effect in the anomalous suppression
We report on a search for a phase transition from ordinary nuclear matter to a state of deconfined quarks and gluons as predicted by lattice QCD calculations. A new measurement of charmonium production in Pb-Pb interactions at 158 GeV/c per nucleon agrees with our previous results and confirms the anomalous suppression we had already observed on a significantly smaller data sample. New event selection and analysis techniques show that, for peripheral collisions, the cross-section per nucleon-nucleon collision agrees with the precise suppression pattern inferred from a wide range of measurements extending from up to S-U collisions. As the collisions become more central, the Pb-Pb cross-section exhibits a clear departure from this normal behaviour. The onset of the anomalous suppression reported here is the first clear observation of a threshold effect in heavy ion collisions and can be considered as a strong indication of the production of a deconfined quark-gluon phase in central Pb-Pb collisions
Pré-tratamento com ácido sulfúrico na germinação de sementes de Ziziphus joazeiro Mart.: Rhamnaceae
Crescimento dos tecidos muscular e adiposo de fêmeas bovinas de diferentes grupos genéticos no modelo biológico superprecoce
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